1. Field of the Invention
This invention relates to an adjustable hitch for attachment to motor vehicles, and in particular to a height adjustable hitch with dual, rotatably selectable hitch balls for the purpose of towing a hitched load such as a trailer.
2. Background & Description of the Related Art
Hitches are devices that connect a tow vehicle to a trailer vehicle by means of a hitch ball mounted on the tow vehicle or tow bar. The hitch ball of the tow vehicle couples to a ball socket located on the trailer vehicle or trailer tongue. This ball and socket configuration has long been known to allow adequate rotation of the socket with respect to the ball so that the coupled tow and trailer vehicles can maneuver turns and pass over vertical road variations without shearing or otherwise damaging the coupling mechanism. Typically, the socket mechanism has a latchable and preferably lockable coupling so that it locks onto the hitch ball to prevent decoupling while towing.
A problem with conventional hitches occurs when the hitch ball is higher or lower than the ball socket. For example, the ball socket of the trailer hitch may rest below the horizontal plane of the hitch ball on the towing vehicle so that the trailer vehicle must first be jacked up or elevated to allow the hitch ball to be positioned under the ball socket. The prior art teaches an integrated jack, among other methods, to accomplish the elevation of the trailer vehicle and attached hitch ball. Incorrect hitch ball height may cause uneven load distribution of the trailer and unsafe towing operation or excessive or uneven wear on the tires. Some hitches have no means of adjusting the vertical position of the hitch ball. Other hitches with vertical adjustment mechanisms are time consuming to adjust because they require replacing parts of the hitch to obtain a suitable height.
With the purpose of overcoming these problems, several types of hitches have been developed to adjust the hitch ball height on the towing vehicle to correspond more appropriately with the ball socket height on the trailer vehicle. Generally, the prior art discloses a height adjustable hitch ball having a vertical bar slidably received by a sleeve. The height of the hitch ball is adjusted by sliding the vertical bar vertically through the sleeve and selectively fixing a desired vertical position of the hitch ball by inserting a pin through the vertical bar and sleeve.
Alternatively, the vertical bar and hitch ball may be fixed in a desired position by fastening the components together with threaded fasteners. For example, U.S. Pat. No. 7,451,996 to Miles et al. teaches a hitch assembly comprising a vertically adjustable bar secured within a mounting sleeve which in turn is securely attached to a hitch bar. A hitch ball is attached to the vertical bar. A vertical securing pin attached to the mounting sleeve releasably engages the vertical bar and is maintained in place by a spring, the pin and spring comprising the vertical securing mechanism. The vertical bar has a series of holes in which the vertical securing pin may be selectively engaged depending on the desired vertical position of the hitch ball. This apparatus allows the hitch ball position relative to a towing ball socket to be vertically adjusted without requiring removal of any parts. Similarly, U.S. Pat. No. 6,824,156 to Smith teaches an adjustable hitch assembly which mates with standard hitch receivers and hitch balls such that the relative height of the hitch ball may be varied during use. The hitch assembly includes an elongated housing, a threaded shaft in the housing, a coupling member on the shaft, a carriage member secured to the coupling member, a rotatable drive that turns the shaft to advance the coupling member and carriage member, a first member secured to the housing for connection to one of the vehicles and a second member secured to the carriage for connection to the other vehicle. This allows the effective height of the hitch assembly to be varied so that different towing situations can be accommodated.
The prior art has also been developed to provide a plurality of hitch balls on a single hitch assembly. These hitch assemblies generally allow for a user to selectively rotate an assembly for use of a desired hitch ball. The selection of a desired hitch ball typically depends on a required hitch ball size for a particular ball socket. For example, U.S. Pat. No. 7,021,643 to Buchanan teaches a carousel trailer hitch providing an adaptive hitch for a box trailer hitch mounted underneath a vehicle bumper attached to a vehicle frame. The carousel hitch includes a box hitch attaching end to which is attached an angled spindle having a rotating carousel base member having a plurality of angled support arms, upon which is provided a plurality of varied ball hitches and implement hitch which may be rotated without being impeded by the bumper of the vehicle by the carousel base member being presented at an angle. The angle of the support arms allows the carousel to be selectively rotated for desired use of one of the plurality of hitch balls. The selected rotation is locked into place by inserting a lock pin into the stem of the rotatable carousel. U.S. Pat. No. 7,004,492 to Moss et al. also discloses a hitch assembly for presenting different sized hitch balls. The hitch includes a first ball and pedestal extending in a first direction and a second ball and pedestal extending in a second direction forming a monolith. A stem extends from the monolith in a third direction. The monolith is selectively rotated about the longitudinal axis of the stem to a desired hitch ball position.
The prior art has also been developed to provide for stowing of the hitch ball without the need to remove components of the hitch assembly from the towing vehicle. For example, U.S. Pat. No. 6,460,870 to Moss teaches a trunnion, adapted to fit in a receiver, attached to a vehicle as a receiver-type hitch system to provide for selective deployment and stowage of a hitch. In certain embodiments, the trunnion connects to a pivot which connects a base to a hitch. A base supports a mount, which may be moved between a stowed and a deployed position. The base includes parallel deployment and pivot apertures in which a lock or locking pin is received therethrough to secure the mount in the deployed or stowed positions, respectively.
It is common for a hitch user to desire multiple adjustments to a hitch assembly during the course of use. For example, as illustrated by the improvements in the prior art discussed above, a user may desire to adjust the height of the hitch ball, adjust the size of the hitch ball, and stow the hitch assembly when not in use. The prior art requires each of these adjustments to be done separately and with separate mechanisms fixing each adjustment in the desired position. Commonly, the mechanisms are fixed in a desired position by inserting a removable locking pin to engage the components in the desired position. However, removable locking pins may be lost, dropped, stolen or become seized in place. For adjustments requiring tightening and loosening of threaded fasteners, tools required for tightening or loosening of threaded fasteners may not be readily available when the adjustment is desired. An improvement over the prior art is needed that allows a user to easily make multiple adjustments, namely, hitch ball height, hitch ball size and stow/use position to a hitch assembly without the need for multiple locking mechanisms and tools.